Alternating-current-motor control.



F. EIOHBERG.

ALTERNATING CURRENT MOTOR CONTROL.

APPLICATION FILED 001226, 1906.

Patented May 4, 1909.

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FRlEDRICH EICH BERG, OF BERLIN, GERMANY, ASSIGNOR TO GEN Eli-1A1, ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ALTERNATING -C'UBR-E NTJQGTOR SON Application .do

To all whom it may (07 266791. Be it known that l, Femnsrcn EICHBEBG, a subiect of the Emperor of EurstriwH-ungary, residing at Berlin, Germany. have invented certain new and useful improvements in Alternating-Current-Motor Control, of which the following is a specification.

My invention relates to the control 0! alternating-current motors ol' the commutator type, and particularly to the type of motor having a statorwinding,commutator brushes short-circuiting the rotor winding on the line of magnetization of the stator winding, and a second set of commutator brushes displaced approximately ninety electrical degrees from the first set. g

My invention consists in employing the short-circuited brushes as one rotor terminal at starting, and employing the the brushes of the second set as the two terminals for running.

My invention will best be understood by reference to the accompanying drawings, in Which Figure 1 shows diagrammatically an alternating-current motor of the commutator type arranged for control in accordance with my invention; Fig. 2 shows an rn'rangement for controlling two motors in parallel; and Fig. 3 shows an arrangement for controlling two motors in series.

In Fig. 1, A represents the stator winding, which is connected in series with the rotor ling B through the commutator brushes hich are arranged on a line displaced nin' I electrical degrees from the line of magnetization of the stator winding. b I) represent brushes arranged to short-circuit the rotor on the line of magnetization of the stator Winding, so that there is a flow of current in the rotor Winding induced by the stator winding; C represents a switch ar ranged. to connect the lead 1 from the source or" current either to the upper brush b, or to the short-circuited brushes Z). The other lea-d 2' from the source is connected to a terminal of the stator winding. With the switch C in the position shown, one-half the rotor turns are cut out of circuit. The current enters the rotor at the lower brush 1), and leaves at the brushes 5. This. is the starting position of the switch. When the switch is thrown into its other position for runnin the current enters the rotor at the lower lh ush b, and leaves at the upper brush Patented. ma 4, recs.

ol' the switch s are tried, rela- C, the rotor :i-rnper :ndinp; in the ratio of tively to the stator x. 2 to l.

The same ployed in a Iil control may be emwith a. plurality of motors.

in Fig. are shown con nected ii -..nd a tadpole, double l to connect one to the lower n ....cuited brushes witch C" is thrown to its upper iositien, cutting one-hall of the rotor turns out of ircuit, and for running, the switch is thrown to its lower position, so that all the rotor turns are in circuit.

Fig. 3 shows a suitable arrangement for controlling two motors in series. For start ing,'switch opened, and switch C is closed. For running, switch is opened and switch C is closed, as shown in the figure.

l hat ll claim as new and desire to secure by Letters Patent of the Uniter States, is,--

1. The method of controlling an alternatin' -current motor of the connnutator type lutving a constantnumber of field poles and having a plurality of sets of conunutator brushes, which consists in employing as rotor terminals at starting; brushes displaced from each other less than one hundred and eighty electrical degrees, and in employing as tcrn'iinals for running brushes displaced from each other by one hundred and eighty electrical degrees.

2. The method of controlling an alternating-currrnit motor of the commutator type having a stator winding, a rotor winding, a set 01 commutator brushes and connections short-circuiting the rotor substantially on the line of magnetization of the stator winding,- and a second set of brushes displaced substantially ninety electrical degrees from the first set, which consists in employing the ,oircuiting the rotor substantially on the line of magnetization of the stator Winding, and

a second set of brushes-displaced substan-' a second set of brushes displaced substantially ninety electrical degrees from the first set, supply leads for the rotor, and a switch arranged to connect said supply leads alter nately to the short-circuiting brushes and one brush of the second set and to the two brushes of the second set.

In witness whereof, I have hereunto set my hand this 11th day of October, 1906. FRIEDRICH EICHBERG. \Vitnesses LIONEL FLEISQHMANN, EMANUEL RosENBERe. 

